spring的自动装配问题

我想在ManagerBean.java中自动装配ManagerService或ManagerDao,但是运行时总是空指针错误。

图为目录结构

//别名

@Alias("manager")
public class Manager {
    private Integer managerId;
    private Integer departmentId;
    private String name;
    private String pass;
    private String phone;
    private String mail;
    private String wechat;
    private String weibo;
    private Integer state;
    private Date createDate;
    private String departmentName;  
     
    @Autowired
    private DepartmentService service;
     
..........
..........
..........
        public boolean isLeafDepartmentManager(){
        List<Department> list = new ArrayList<Department>();
        list =     service.querySubordinate(this.departmentId.toString());      
        return list.size() == 0;
    }